This proposal is based on development of a novel analytical assay to detect single nucleotide polymorphisms (SNPs). The investigators propose the use of peptide nucleic acid (PNA)-oligonucleotides as probes, due to their advantages in hybridization kinetics and affinity-capture techniques. The investigators plan to detect target sequences complementary to the PNA probe with an anti- fluorescein Ab-HRP conjugate, using colloidal gold sensors to detect the byproduct of the HRP-catalyzed reaction as a change in current. The proposed instrumentation and assay may provide the basis for developing a high-throughput, automated and economical method of identifying SNPs. PROPOSED COMMERCIAL APPLICATION: The new SNP scoring system proposed here is founded on a versatile, automated chip-based system for probe analysis of DNA or RNA. It will serve as a companion instrument to PCR as a new tool for nucleic acid analysis. The laboratory market for PCR is currently $300 million per year. Our PCR-related system would represent a significant new, complementary product in this marketplace. Furthermore, as the clinical market matures, we anticipate a range of diagnostic applications that will increase the market for the instrument.